When to Cut Butterfly Bush Blooms?

Whether you grow them for their spikes of flowers or their ability to attract hummingbirds and butterflies, butterfly bushes (Buddleja davidii) make an attractive addition to sun-filled gardens. These shrubs thrive in U.S. Department of Agriculture hardiness zones 5 through 10 and bloom throughout the summer. To keep your butterfly bush tidy and to prevent it from becoming invasive, cut back the flower heads regularly.

Cutting for Flowers

Although they look lovely in the garden, it's hard to resist adding butterfly bush flower heads to an indoor vase. You can cut any flower head off your shrub, but the flowers will last longer indoors if you select spikes on which flowers are just beginning to open. Taking cut flowers can be done anytime while the plant is in bloom, but it's best to cut the flowers in the morning when they are at their freshest. Once cut, place the flowers in water as soon as possible.

Fading Blooms

The flowers on your butterfly bush bloom and die back throughout the bloom period. These dead flowers detract from the beauty of your shrub. As soon as you notice flowers starting to fade, cut them back. If you trim the spent flower spikes back to the next flower node on the branch, this will encourage your butterfly bush to bloom again. Because butterfly bushes flower throughout the summer, dead heading should be done weekly during the summer.

Invasive Speices Prevention

The seeds of butterfly bushes spread and sprout easily which elevates this shrub's invasive potential. In Oregon, the plant is listed as invasive and other states have declared it a noxious weed. To keep your butterfly bush's seeds from invading natural areas, it's vital to cut back the flower heads before they go to seed. Throughout the summer and into early fall, remove any faded flower spikes you see on your butterfly bush. Continue this chore until the plant stops flowering in early fall.

Pruning for Flowers

To encourage your butterfly bush to produce more flowers and to control the height of your shrub, prune the plant back in early spring before new growth begins. With clean loppers, cut each branch back to a height of 12 inches. This heavy pruning causes the plant to branch out with new stems. Since butterfly bushes bloom mainly on new stems, you'll end up with more flowers than if you don't prune the shrub.

About the Author

Based in Portland, Ore., Tammie Painter has been writing garden, fitness, science and travel articles since 2008. Her articles have appeared in magazines such as "Herb Companion" and "Northwest Travel" and she is the author of six books. Painter earned her Bachelor of Science in biology from Portland State University.